diff options
Diffstat (limited to 'stdio')
| -rw-r--r-- | stdio/internals.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/stdio/internals.c b/stdio/internals.c index c238bf39f9..acdf97783a 100644 --- a/stdio/internals.c +++ b/stdio/internals.c @@ -199,9 +199,14 @@ DEFUN(flushbuf, (fp, c), size_t buffer_offset = 0; - /* If the user has read some of the buffer, the target position - is incremented for each character he has read. */ - fp->__target += fp->__bufp - fp->__buffer; + if (fp->__target == -1) + /* For an unseekable object, data recently read bears no relation + to data we will write later. Discard the buffer. */ + fp->__get_limit = fp->__buffer; + else + /* If the user has read some of the buffer, the target position + is incremented for each character he has read. */ + fp->__target += fp->__bufp - fp->__buffer; if (fp->__mode.__read && fp->__room_funcs.__input != NULL && !fp->__mode.__append) @@ -231,12 +236,12 @@ DEFUN(flushbuf, (fp, c), /* Start bufp as far into the buffer as we were into this block before we read it. */ buffer_offset = o; - } - /* The target position is now set to where the beginning of the - buffer maps to; and the get_limit was set by the input-room - function. */ - twiddled = 1; + /* The target position is now set to where the beginning of the + buffer maps to; and the get_limit was set by the input-room + function. */ + twiddled = 1; + } } if (fp->__buffer != NULL) @@ -289,7 +294,8 @@ DEFUN(flushbuf, (fp, c), call with nothing in the buffer, so just say the buffer's been flushed, increment the file offset, and return. */ fp->__bufp = fp->__buffer; - fp->__offset += to_write; + if (fp->__offset != -1) + fp->__offset += to_write; goto end; } @@ -315,7 +321,7 @@ DEFUN(flushbuf, (fp, c), bother to find the current position; we can get it later if we need it. */ fp->__offset = fp->__target = -1; - else + else if (fp->__offset != -1) /* Record that we've moved forward in the file. */ fp->__offset += wrote; } @@ -339,7 +345,7 @@ DEFUN(flushbuf, (fp, c), char cc = (unsigned char) c; if ((*fp->__io_funcs.__write)(fp->__cookie, &cc, 1) < 1) fp->__error = 1; - else + else if (fp->__offset != -1) { /* Record that we've moved forward in the file. */ ++fp->__offset; @@ -355,9 +361,10 @@ DEFUN(flushbuf, (fp, c), if (!twiddled) { - /* The new target position moves up as - much as the user wrote into the buffer. */ - fp->__target += buffer_written; + if (fp->__target != -1) + /* The new target position moves up as + much as the user wrote into the buffer. */ + fp->__target += buffer_written; /* Set the reading limit to the beginning of the buffer, so the next `getc' will call __fillbf. */ @@ -433,8 +440,9 @@ DEFUN(fillbuf, (fp), register FILE *fp) buffer += count; nread += count; to_read -= count; - /* Record that we've moved forward in the file. */ - fp->__offset += count; + if (fp->__offset != -1) + /* Record that we've moved forward in the file. */ + fp->__offset += count; } } |